Atherosclerosis, or hardening of the arteries, is usually thought of as a modern disease brought on by fatty diets, smoking and lack of exercise. But new studies of mummies from around the world show that the disease is an ancient affliction with a plethora of possible triggers.
In the June Global Heart, researchers present evidence of heart disease from a diverse array of mummies including the famous 5,300-year-old Tyrolean Iceman, 76 ancient Egyptians, 51 native Peruvians dating from the 3rd to 16th centuries, five Pueblo Indians who lived in Utah about 1,000 years ago, a Renaissance king, a 15th century nomad from the Gobi Desert and five 19th century hunter-gatherers from the Aleutian Islands. CT scans or autopsies revealed calcium deposits in artery walls of many of the mummies, a sign of vessel hardening.
Atherosclerosis results when plaque composed of cholesterol and other substances builds up on the interior walls of arteries. That plaque can nucleate a blood clot or break away in bits to clog the arteries and cause heart attacks or strokes. Cardiovascular disease is the leading cause of death in the United States, killing about 600,000 people each year.The mummy studies present compelling evidence that people developed atherosclerosis “even in an environment where exercise was abundant and fast food was nonexistent,” says Matthew Budoff, a cardiologist at UCLA who was not involved in the work.
The project was born in 2008 when cardiologists Gregory Thomas of the University of California, Irvine and Adel Allam of Al-Azhar University in Cairo visited Cairo’s Egyptian Museum. A sign by the mummy of the pharaoh Menephtah said that the ruler had died in his 60s of atherosclerosis.
Thomas and Allam decided to test the claim by scanning the pharaoh and other Egyptian mummies. The disease was easy to find in 2,000- to 3,500-year-old Egyptian elites, the researchers and their team reported in 2009 (SN: 12/19/09, p. 14). The project has since grown to include mummies of people who lived on five continents, ate a wide range of diets and followed varying lifestyles.
The team has now compared the cardiovascular systems of 76 Egyptian mummies with the blood vessels of 178 modern Egyptian cancer patients. Hardening arteries appeared in about 38 percent of the mummies and more than 60 percent of the present-day people. When the researchers accounted for the ancient people’s shorter life spans — the mummified people had died on average at age 36, while the modern Egyptians had an average age of 52 — the team discovered that ancient and modern people’s diseases were nearly indistinguishable, Allam says. The arteries that were hardened in the modern people were the same ones with plaque buildup in the mummies.
The researchers also found calcified plaques in the arteries of 37 percent of mummies from Peru, the American Southwest and the Aleutian Islands.
“Their findings are provocative,” says Nathan Wong, a cardiologist at the University of California, Irvine. He thinks that atherosclerosis may have been even more prevalent in the ancient people than the studies indicate. It is hard to detect because some of the mummies were not well preserved.
Rulers, such as the Egyptian pharaohs and the obese 15th century King Ferdinand I of Naples, ate meaty diets and had sedentary lifestyles that could foster the disease, just as they do in modern people. But the other mummified people didn’t have such rich diets and got plenty of exercise. None of them smoked tobacco. Their atherosclerosis must have sprung from other sources, the researchers reasoned.
Increasingly, scientists are thinking of atherosclerosis as a product of genetics and aging, says Thomas. “We haven’t been able to find a culture that doesn’t get blockages of their arteries.” That commonality suggests that atherosclerosis may be errors “baked into human genes,” he says. Or the genetic underpinnings of heart disease may provide some hidden benefit early in development or may have helped humans evolve better defenses against infectious diseases, he says.
At least one of the mummies, the Tyrolean Iceman known as Ötzi, had genetic variants that, in modern people, have been linked to heart disease, report researchers led by Albert Zink, a paleopathologist who directs the Institute for Mummies and the Iceman in Bolzano, Italy.
The combination of variants in Ötzi’s genome would have doubled his chance of getting heart disease.
At the time of his death in his 40s, the Iceman had atherosclerosis. An arrow to the back killed him. “It’s possible that if he wasn’t killed by this arrow, he could have died of a heart attack or stroke 10 years later,” Zink says.
The researchers hope to conduct DNA analyses on the other mummies to see whether they also carry genetic variants that could spur heart disease.
But bad genes are no guarantee that someone will get heart disease, says David Hunt, a physical anthropologist at the Smithsonian Institution in Washington, D.C., who was not involved in the work. Environmental factors, such as diet, exercise, smoking habits and exposure to pollution are needed to bring on the disease, he says. “Genetics loads the bullets in the gun, but environment pulls the trigger,” Hunt says.
Exactly what the trigger pullers were in ancient times is still a matter of debate. The researchers speculate that inhaling smoke from indoor cooking fires could have been the ancient health-wrecking equivalent of today’s cigarette smoking. Autopsies of two Aleutian Islanders revealed soot in their lungs, and CT scans showed that three of five examined had atherosclerosis.
Inflammation caused by chronic infections may also have brought on the disease, the researchers say. Many of the mummies studied carried parasites and evidence of other infections.
And don’t forget about stress, says coauthor Randall Thompson, a cardiologist at Saint Luke’s Mid America Heart Institute in Kansas City, Mo. “People think in earlier times it was a simpler, more natural life,” he says, but disease, weather, food shortages, cultural conflict and other difficulties of the ancient world could have produced stress to rival anything modern society dishes out.
As for Menephtah, the mummy that inspired the studies, his wrappings were unwound in 1907 and an autopsy uncovered “large bonelike patches” in the walls of his aorta. Allam’s team was unaware there had been an autopsy when it began its work, Allam says. CT scans confirmed the atherosclerosis diagnosis, he says.
While the researchers can’t say for certain that Menephtah died of heart disease, Allam says, “We would have put him as a high-risk patient.”